This invention concerns a method of spraying liquids under the form of foam produced by means of containers deformed by being manually squeezed and also the device that uses this method.
It is common knowledge that the market is seeing an increasing diffusion of deformable containers made of plastic that by the pressure of a hand and by means of suitable devices, spray a mixture of liquid and air under the form of a foam.
These containers are gaining more and more significant market segments because they are versatile and overcome several environmental problems. In effect, these containers can spray foams without resorting to special, pressurized gases. What""s more both the containers, and the devices that dispense these mixtures, are preferably made entirely of plastic and therefore have a minimal environmental impact since the plastic can be recycled and they do not have other materials such as for example metal or likewise any incompatible materials with the actual plastic. Moreover, these containers can be refilled after their first use and therefore be used for several recharges. These kinds of foam forming devices have the most diverse fields of use. In the cleaning sector foams are produced for cleaning bathrooms, windows, for cleaning for instance kitchen ovens, for cleaning furniture or for dispensing soap, shampoo, or facial care products. With regards to personal health and hygiene, foam-based products are found for instance in hand, hair and skin care products, for creating shaving foam, or furthermore for cleaning products for pets such as dogs and cats. There are also applications in specific medical sectors such as for example foams for protective sun lotions to be applied to the skin, and many more.
There are essentially two devices on the market capable of spraying foams without pressurized gas: one type prescribes the use of a hand operated pump and mixes air and liquid in a mixing chamber to then form the foam. De-U-91 10 905 discloses a container with a manual spraying device having a first body coupled with the container and having a second body in which it arrives the liquid of the container to be mixed in a mix chamber with the air. Other devices can be found on the market that operate by squeezing the container by means of hand pressure, these consist of a cap applied to the neck of the bottle, which encloses a chamber that, when the container is squeezed by hand, receives the liquid sucked up by a suction tube in the container and the air contained in the container itself. The mixture of liquid and air collected in this chamber is discharged from the chamber by the introduction of additional liquid and an additional input of air and is transformed into foam since the outlet duct for this mixture has a filter element provided with suitable pinholes that allow, also as a function of the liquid""s viscosity characteristics and the quantity of air mixed with said liquid, to produce a discharge of the mixture under foam form. These types of containers can be used both upright and overturned. It has been noted that when the container operates overturned, for instance to dispense the foam on sanitary units or oven hobs or on anything else, the first spray that comes from the container is made under liquid form and not foam. All this is because the liquid contained in the suction tube inside the container is discharged by gravity at such a speed that it does not permit the correct mixture between liquid and air.
The main scope of this invention is to produce a method of spraying liquid contained in a deformable container under the form of foam and a device that performs this method, in such a way that, right from the first spray, it however and always ensures that the product discharged from the container is dispensed under foam form and not in liquid form. A particular intention is to ensure that the first spray is under foam form regardless of whether the container is squeezed in an upright or overturned position.
Another scope is to ensure a constant quality during each spray and regardless of the liquid that is dispensed.
Last but not least, a scope of this invention is to produce a device that is inexpensive, easy to construct and also easy to assemble, even with automated type equipment.
The invention""s scopes are achieved by a spraying device for liquids to dispense under foam form by manually squeezing and deforming a container the main features of said spraying device being according to claim 1.
The invention also produces a method of spraying an air-liquid mixture under foam form from the spraying device of the type described above, where said method comprises:
at least one first liquid expelling stage from the suction tube by hand squeezing and deforming the container;
a second introduction stage of air into the container;
a third further squeezing stage of the container with spraying of the mixture under foam form, said method being characterized in that during said first expelling stage said liquid is collected and held inside said second chamber belonging to said device.
One advantage according to the invention is that, by creating a second chamber in the device, to contain the liquid sucked up from the suction tube, this prevents the first spray with the container, whether it is upright or overturned, from creating a condition where the product is sprayed in liquid form and not under the form of foam.